1. Field of the Invention
The invention relates to electronic program guides and, more particularly, the invention relates to a technique for encoding a user interface of an information distribution system.
2. Description of the Background Art
In several communications systems, the data to be transmitted is compressed so that the available transmission bandwidth is used more efficiently. For example, the Moving Pictures Experts Group (MPEG) has promulgated several standards relating to digital data delivery systems. The first, known as MPEG-1 refers to ISO/IEC standards 11172 and is incorporated herein by reference. The second, known as MPEG-2, refers to ISO/IEC standards 13818 and is also incorporated herein by reference. A compressed digital video system is described in the Advanced Television Systems Committee (ATSC) digital television standard document A/53, and is incorporated herein by reference.
The above-referenced standards describe data processing and manipulation techniques that are well suited to the compression and delivery of video, audio and other information using fixed or variable rate digital communications systems. In particular, the above-referenced standards, and other xe2x80x9cMPEG-likexe2x80x9d standards and techniques, compress, illustratively, video information using intra-frame coding techniques (such as run-length coding, Huffman coding and the like) and inter-frame coding techniques (such as forward and backward predictive coding, motion compensation and the like). Specifically, in the case of video processing systems, MPEG and MPEG-like video processing systems are characterized by prediction-based compression encoding of video frames with or without intra- and/or inter-frame motion compensation encoding.
Over the past few years, television has seen a transformation in a variety of means by which its programming is distributed to consumers. Cable television systems are doubling or even tripling system bandwidth with the migration to hybrid fiber coax (HFC) cable plant thereby offering a larger number of channels to the viewer. Customers unsatisfied with their local cable systems have switched in high numbers to direct broadcast satellite (DBS) systems. And, a variety of other approaches have been attempted focusing primarily on high bandwidth digital technologies, intelligent two way set top boxes, or other methods of trying to offer service differentiated from standard cable and over the air broadcast systems.
With this increase in bandwidth, the number of programming choices has also increased. Leveraging off the availability of more intelligent set top boxes, several companies such as Starsight and Prevue Guide have developed elaborate systems for providing an interactive listing of a vast array of channel offerings, expanded textual information about individual programs, the ability to look forward to plan television viewing as much as several weeks in advance, and the option of automatically programming a VCR to record a future broadcast of a television program.
Unfortunately, the existing program guides have several drawbacks. They tend to require a lot of memory, some of them needing upwards of one megabyte of set top terminal (STT) memory. They are very slow to acquire their current database when they are activated for the first time or are subsequently restarted (e.g., a large database may be downloaded to a STT using only a vertical blanking interval (VBI) data insertion technique). Disadvantageously, such slow database acquisition may result in out of date database information or, in the case of a pay per view (PPV) or video-on-demand (VOD) system, limited scheduling flexibility for the information provider. The user interface to existing program guides does not usually look like a typical television control interface; rather looks like a 1980""s style computer display (i.e., blocky, ill-formed text and/or graphics).
Additionally, the present program guides may provide an advertising or preview region along with the program guide graphics. However, the insertion of these additional video signals is performed using an analog compositor that merely inserts (overlays) the additional imagery into the broadcast stream. The analog compositing process is accomplished and then the new analog video containing an advertisement or preview and the program guide are recorded on tape for subsequent broadcast. This compositing process is not accomplished in real time at the head end of the cable system and, consequently, the program guide can not contain targeted advertising for a particular household or a particular neighborhood or region. The program guide with its associated preview or advertising is broadcast to all subscribers connected to the head end of the cable system. Additionally, these program guides are generally passive, in that, the viewer sees the program guide information change on the screen to indicate different programs and their associated channels. However, there is no provision enabling a viewer to interact with the program guide display to scroll through the channel or channels that are available. Because such scrolling in an analog system requires a splice to a new program guide video sequence, the program guides that are interactive do not include advertising video or other video information with the program guide.
Therefore, it is desirable to provide a method and apparatus for encoding an interactive program guide.
The disadvantages associated with the prior art are overcome by the present invention of a method and apparatus for encoding user interface of an information distribution system. One embodiment of such user interface is an interactive program guide (IPG) that forms an IPG screen or page containing a graphical guide region and a video region playing at least one video sequence. The invention is a method and apparatus for performing ensemble encoding of one or more IPG pages. The invention comprises a plurality of compositors that combine background information, informational video and program guide graphics into a single sequence of video frames. The sequence is then digitally encoded to form an MPEG-like bitstream. The same background information and informational video is composited with a different program guide graphic to form another video sequence that is also encoded. A plurality of such bitstreams are produced with each sequence containing a different program guide graphic. The encoding is performed using a common coding profile and a common clock for each of the encoders. The encoded sequences are then multiplexed into at least one transport stream such that all the encoded sequences are transmitted to subscriber equipment using one or more transport streams. As such, the subscriber can transition from one program guide page to the next without interruption of the background or informational video as the program guide page graphic is changed.
The informational video may appear in multiple locations upon the IPG screen. Promotional or advertising video may appear in one portion while an animated graphic appears in another location. Each of the informational video streams may have a different rate of display. The encoders handle different video rates by using slice based encoding of the composite image sequence.
One example of a program guide that is encoded in accordance with the invention has each graphic containing a set of programs (e.g., channels) listed along a left, vertical axis and each program associated with the channel is identified in a rectangular cell that extends toward the right. The horizontal axis represents time and about 1.5 hour of programming for ten channels is shown in each program guide graphic page. The informational video is generally contained in one or more regions above the program graphic.
In another example of a program guide that is encoded in accordance with the invention has each graphic containing a set of programs (e.g., channels) listed along a left, vertical axis and each program associated with the channel is identified in a cell that is listed beneath a time axis. The horizontal axis represents time and about 1.5 hours of programming for eight channels is shown in each program guide graphic page. Each channel is associated with text that represents three programming slots, one for each half hour in the time axis. The informational video is generally contained in one or more regions next to the program graphic, i.e., a guide region is on the left half of the screen and the video region is on the right half of the screen or vice versa.